IB Buy on Nasdaq & Sell on Best ECN

Strategy
Put a buy order on Nasdaq & Sell on Best ECN
Have anyone tried this strategy?
How did it turn out?
What stocks do you trade this way & how many shares?
How many times get excuted?
If this strategy works, you will get advantage of price difference between Nasdaq & best ECN
However, I doubt about the excute speed on Nasdaq
Any comments?